Process for producing an amino acid-N, N-diacetic acid and its salts

Abstract

An amino acid-N,N-diacetic acid (AADA) or its salt with an equivalent or less of an alkali metal is produced by reducing, through electrodialysis, alkali metal ions from an aqueous solution of the alkali metal salt of an AADA. By this configuration, an AADA salt can be produced in a much higher yield than conventional equivalents without requiring a regeneration operation of a resin as in the use of an ion exchange resin or without requiring crystallization-separation of crystals of the AADA salt as in the addition of an organic solvent. A salt of an amino acid-N,N-diacetic acid is also produced by reacting an AADA with any of metal oxides, metal hydroxides, metal carbonates, metal hydrogencarbonates, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate or organic amine compounds. By this configuration, a metal salt, aromonium salt or organic amine salt of an AADA can be produced with efficiency without the formation of by-products.

What is claimed is:  
     
       1. A magnesium salt of an amino acid-N,N-diacetic acid, which is a salt of an amino acid-N,N-diacetic acid obtainable by a process comprising: 
       reducing alkali metal ions from an aqueous solution of an alkali metal salt of said amino acid-N,N-diacetic acid by electrodialysis to produce an amino acid-N,N-diacetic acid,  
       wherein said alkali metal salt of an amino acid-N,N-diacetic acid is a salt represented by the following formula (1):                    
       wherein M represents an alkali metal, m represents 0 or an integer of from 1 to 2, and n represents 0 or an integer of from 1 to 3; and  
       reacting said amino acid-N,N-diacetic acid with a metal oxide, a metal hydroxide, a metal carbonate, a metal hydrogencarbonate, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate, or an organic amine compound.  
       wherein 0.5 to 1 equivalent of a magnesium compound is reacted with 1 equivalent of a carboxyl group.  
     
     
       2. A bleaching agent composition comprising the magnesium salt of amino acid-N,N-diacetic acid of  claim 1  and an oxygen bleaching base. 
     
     
       3. A magnesium salt of an amino acid-N,N-diacetic acid, which is a salt of an amino acid-N,N-diacetic acid obtainable by a process comprising: 
       reducing alkali metal ions from an aqueous solution of an alkali metal salt of said amino acid-N,N-diacetic acid by electrodialysis to produce an amino acid-N,N-diacetic acid,  
       wherein said alkali metal salt of an amino acid-N,N-diacetic acid is a salt represented by the following formula (1):                    
       wherein M represents an alkali metal, m represents 0 or an integer of from 1 to 2, and n represents 0 or an integer of from 1 to 3; and  
       reacting said amino acid-N,N-diacetic acid with a metal oxide, a metal hydroxide, a metal carbonate, a metal hydrogencarbonate, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate, or an organic amine compound  
       wherein said amino acid-N,N-diacetic acid is glutamic acid-N,N-diacetic acid, and  
       wherein 0.5 to 1 equivalent of a magnesium compound is reacted with 1 equivalent of a carboxyl group.  
     
     
       4. A bleaching agent composition comprising the magnesium salt of amino acid-N,N-diacetic acid of  claim 3  and an oxygen bleaching base.